BACKGROUND Several factors are known to interfere with electrocardiogram (ECG) sensitivity when diagnosing Left Ventricular Hypertrophy (LVH), with gender and cardiac mass being two of the most important ones OBJECTIVE To evaluate the influence of gender on the sensitivity of some of the criteria used to detect LVH, according to the progression of ventricular hypertrophy degree. METHODS According to gender and the degree of LVH at the echocardiogram, the patients were divided in three groups: mild, moderate and severe LVH. ECG sensitivity to detect LVH was assessed between men and women, according to the LVH degree. RESULTS Of the 874 patients, 265 were males (30.3%) and 609, females (69.7%). The [(S + R) X QRS], Sokolow-Lyon, Romhilt-Estes, Perugia and strain criteria showed high discriminatory power in the diagnosis of LVH between men and women in the three groups with LVH, with a superior performance in the male population and highlighting the importance of the [(S + R) X QRS] and Perugia scores. Conclusion: The diagnostic sensitivity of the ECG increases with the cardiac mass. The examination is more sensitive in men, highlighting the importance of the [(S + R) X QRS] and Perugia scores. CONCLUSIONS The diagnostic sensitivity of the ECG increases with the cardiac mass. The examination is more sensitive in men, highlighting the importance of the [(S + R) X QRS] and Perugia scores.